Objective: Current studies focus on the prevalence rate of lung cancer in idiopathic pulmonary fibrosis and connective tissue disease-associated interstitial lung disease (CTD-LID). Our aim was to investigate the prevalence of malignancies in patients with various subtypes of ILD.
Methods: A total of 5350 patients diagnosed with ILD between January 2015 and December 2021 were retrospectively included. The prevalence of different malignancies and different ILDs was assessed using complete follow-up data.
Results: A total of 248 patients (139 males; 65-IQR, 57 to 72-years) out of 5350 patients with ILD were confirmed with malignancies. A total of 69% of patients with ILD and malignances were older than 60 years old. The prevalence of malignancies in ILD patients was 4.6%, and lung cancer had the most common incidence of 1.9%, followed by malignancies in the digestive system of 0.9%. Among the different ILD subtypes, the prevalence of malignancies such as organizing pneumonia (OP), idiopathic pulmonary fibrosis (IPF), anti-neutrophil cytoplasmic antibodies-associated vasculitis-related ILD(AAV-ILD), nonspecific interstitial pneumonia (NSIP), CTD-ILD, hypersensitivity pneumonitis (HP), sarcoidosis, and other types of ILD was 6.8%, 5.0%, 4.7%, 4.3%, 2.5%, 2.2%, 1.2%, and 6.9%, respectively. The incidence of lung cancer as the most common tumor in IPF was 3.9%, with adenocarcinoma predominating (1.7%). The highest rate of malignancy occurring in RA of CTD-ILD was 2.4%.
Conclusion: Older patients with ILD (≥60 years) including OP, IPF, AAV-ILD, NSIP, CTD-ILD, and HP, were associated with a higher incidence of malignancy, especially males aged from 60 to 69 years. These epidemiological results indicate that it is essential for physicians to pay more attention to the screening of and management strategies for different malignancies, according to the specific ILD subtypes.
Keywords: interstitial lung disease; lung cancer; malignancy; prevalence.